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Java > Open Source Codes > freemarker > ext > beans > MapModel


1 /*
2  * Copyright (c) 2003 The Visigoth Software Society. All rights
3  * reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
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9  * 1. Redistributions of source code must retain the above copyright
10  * notice, this list of conditions and the following disclaimer.
11  *
12  * 2. Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in
14  * the documentation and/or other materials provided with the
15  * distribution.
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17  * 3. The end-user documentation included with the redistribution, if
18  * any, must include the following acknowledgement:
19  * "This product includes software developed by the
20  * Visigoth Software Society (http://www.visigoths.org/)."
21  * Alternately, this acknowledgement may appear in the software itself,
22  * if and wherever such third-party acknowledgements normally appear.
23  *
24  * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
25  * project contributors may be used to endorse or promote products derived
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29  * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
30  * nor may "FreeMarker" or "Visigoth" appear in their names
31  * without prior written permission of the Visigoth Software Society.
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51  */
52
53 package freemarker.ext.beans;
54
55 import java.util.List JavaDoc;
56 import java.util.Map JavaDoc;
57 import java.util.Set JavaDoc;
58
59 import freemarker.ext.util.ModelFactory;
60 import freemarker.template.ObjectWrapper;
61 import freemarker.template.TemplateMethodModelEx;
62 import freemarker.template.TemplateModel;
63 import freemarker.template.TemplateModelException;
64
65 /**
66  * <p>A special case of {@link BeanModel} that adds implementation
67  * for {@link TemplateMethodModelEx} on map objects that is a shortcut for the
68  * <tt>Map.get()</tt> method. Note that if the passed argument itself is a
69  * reflection-wrapper model, then the map lookup will be performed using the
70  * wrapped object as the key. Note that you can call <tt>get()</tt> using the
71  * <tt>map.key</tt> syntax inherited from {@link BeanModel} as well,
72  * however in that case the key is always a string.</p>
73  * <p>The class itself does not implement the {@link freemarker.template.TemplateCollectionModel}.
74  * You can, however use <tt>map.entrySet()</tt>, <tt>map.keySet()</tt>, or
75  * <tt>map.values()</tt> to obtain {@link freemarker.template.TemplateCollectionModel} instances for
76  * various aspects of the map.</p>
77  * @author Attila Szegedi
78  * @version $Id: MapModel.java,v 1.26 2004/01/06 17:06:42 szegedia Exp $
79  */
80 public class MapModel
81 extends
82     StringModel
83 implements
84     TemplateMethodModelEx
85 {
86     static final ModelFactory FACTORY =
87         new ModelFactory()
88         {
89             public TemplateModel create(Object JavaDoc object, ObjectWrapper wrapper)
90             {
91                 return new MapModel((Map JavaDoc)object, (BeansWrapper)wrapper);
92             }
93         };
94
95     /**
96      * Creates a new model that wraps the specified map object.
97      * @param map the map object to wrap into a model.
98      * @param wrapper the {@link BeansWrapper} associated with this model.
99      * Every model has to have an associated {@link BeansWrapper} instance. The
100      * model gains many attributes from its wrapper, including the caching
101      * behavior, method exposure level, method-over-item shadowing policy etc.
102      */
103     public MapModel(Map JavaDoc map, BeansWrapper wrapper)
104     {
105         super(map, wrapper);
106     }
107
108     /**
109      * The first argument is used as a key to call the map's <tt>get</tt> method.
110      */
111     public Object JavaDoc exec(List JavaDoc arguments)
112     throws
113         TemplateModelException
114     {
115         Object JavaDoc key = unwrap((TemplateModel)arguments.get(0));
116         return wrap(((Map JavaDoc)object).get(key));
117     }
118
119     /**
120      * Overridden to invoke the generic get method by casting to Map instead of
121      * through reflection - should yield better performance.
122      */
123     protected TemplateModel invokeGenericGet(Map JavaDoc keyMap, Class JavaDoc clazz, String JavaDoc key)
124     throws TemplateModelException
125     {
126         return wrap(((Map JavaDoc)object).get(key));
127     }
128
129     public boolean isEmpty()
130     {
131         return ((Map JavaDoc)object).isEmpty() && super.isEmpty();
132     }
133
134     public int size()
135     {
136         return keySet().size();
137     }
138
139     protected Set JavaDoc keySet()
140     {
141         Set JavaDoc set = super.keySet();
142         set.addAll(((Map JavaDoc)object).keySet());
143         return set;
144     }
145 }
146
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